You should know that I had a lot of trouble writing paper 3, so that's an area you want to focus on, especially because it has the most weightage. The resources I have may be helpful, but you really need extra help, from textbooks, teachers and lots and lots of practice papers.

A level psychology--I love psychology, but CIE sure makes it a pain--is essentially a memory test. No, it IS a memory test. You have to memorize pretty much the whole course and write it all down in the papers. If you have a bad memory, do NOT take psychology. For the two core studies papers, it may seem like they won't ask for little details, but you're wrong. They will ask for the number of participants, male and female, age group, etc. They will ask for things you will miss if you don't read the original studies. So--read the original studies, and make sure you know pretty much everything about each study. Don't slack off. For Paper 3, you need to do all those studies they point out in the syllabus and there are a whole lot of them. Luckily, for this paper, you only need basic stuff, like things you can find in abstracts, and I'm pretty sure I cover all the studies you need as per my syllabus in the notes. Unlike History and Eng Lit, you can't pick and choose which topics to study--besides choosing the two sections you're going to attempt. And in this case, just choose the two sections (e.g. abnormal, health, environmental, etc) right off the bat, and don't bother going through the others. Be thorough, and practice writing essays. It's highly likely that you run out of time if you don't practice using time limits. These are long papers--you won't have time to stop and gaze out the window.

The sections I chose for p3 were Health Psychology (it's a pain, and I hated doing it, but it seems a simpler option. I don't know. If I could have, I wouldn't have taken this one.) and Abnormal Psychology (abnormal is really interesting, but the paper is dead boring. However, I'd highly recommend this option, because learning about it in a non-CIE fashion is fun. The CIE way...zzzzzzzzzzzzz. But go for it, really)

So, for health Psychology, you have a whole lot of studies you have to know about. Most are covered in this prezi I made (you'll notice that I changed a couple of studies--which is okay--because I couldn't find much on the ones suggested in the syllabus):
http://prezi.com/maqyc7eioc9l/health-psychology/

Good luck! Hope you do better than I think I did.